Figure 4.

Possible links between rheumatoid arthritis (RA) specific anti-cyclic citrullinated peptide (anti-CCP) antibodies and RA-associated genetic factors (see text for details). (a) PADI4 single nucleotide polymorphisms (SNPs) may lead to elevated PAD4 expression and to increased citrullination of proteins [7]. (b) RA-associated HLA-DR4 molecules (DR4) can bind and present citrullinated peptides much more efficiently than noncitrullinated peptides [17]. (c) IL-10 promoter SNPs are associated with increased anti-CCP antibody production and severity of the disease [19]. (d) Various cytokine polymorphisms are associated with RA and may lead to stronger effects of immune complex activated cells. Abs, antibodies; DC, dendritic cell; Fcγ, Fcγ receptor; IC, immune complex; mφ, macrophage; PAD, peptidylarginine deiminase.